Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.11.18 (MAP)
 7,412 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The injection of 25 mg/kg i.p. cyclosporin (CsA) for 3 wk caused marked functional and morphological deteriorations of pancreatic islet cells in Wistar rats that were prevented by the combined administration of p-aminobenzoic acid-N-D-mannoside sodium salt (K-MAP). In this article, the toxic effect of CsA on pancreatic islet cells and the preventive effect of K-MAP on CsA-associated islet cell toxicity were investigated. Prolonged hyperglycemia and depressed insulin secretion after the glucose challenge observed in CsA-treated rats could be prevented by the combined administration of 300 and 900 mg/kg K-MAP. Cytoplasmic vacuolizations and a decrease in the number of mitochondria, intact endoplasmic reticula, secretory granules, and insulin-positive cells, as revealed by peroxidase-antiperoxidase staining, could also be prevented by the administration of 900 mg/kg K-MAP. This preventive effect of K-MAP on CsA-associated islet cell toxicity may suggest the combined use of K-MAP with CsA in pancreas transplantation and treatment of insulin-dependent diabetes.
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PMID:Modulation of prostaglandin metabolism by K-MAP and prevention of toxic effect of cyclosporin on pancreatic islet cells. 264 33

The changes in plasma glucose concentration and hematocrit during, and 7-day survival after, 60-min hemorrhagic hypotension (55 mmHg MAP) were investigated in postprandial and 6- or 24-h food-deprived rats. During hemorrhage, postprandial rats developed hyperglycemia, 30% greater than 6-h and 150% higher than 24-h food-deprived rats. Blood loss and plasma refill were greater in postprandial rats compared to 24-h food-deprived rats. Food deprivation for 24 h resulted in significantly increased mortality (6/13) posthemorrhage. All postprandial rats survived (13/13). A further three groups of animals deprived of food for 24 h were submitted to hemorrhage volume similar to that of postprandial rats. When no infusion was given during hemorrhage all rats died after hemorrhage (10/10). Saline infusion did not increase survival. Infusion of a similar volume of hypertonic glucose resulted in improved survival (not significant vs postprandial). Short-term food deprivation alters responses to stress and influences the outcome after standardized hemorrhage. Induction of hyperglycemia during hemorrhage was associated with survival.
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PMID:Effect of food deprivation on survival after hemorrhage in the rat. 362 80

Twenty-four hour food deprivation increases mortality after experimental hemorrhage. Survival after hemorrhage is closely related to the capacity of the animal to develop hyperglycemia. In this study, 24 hr food deprived rats were given a 3-hr infusion of either 0.3 ml/100 g b.wt./h 30% glucose iv (n = 10) or the same volume of 0.9% NaCl (n = 10) prior to 60 min of standardized hemorrhage. Glucose infusion resulted in a transient hyperglycemia, and 600% greater hepatic glycogen content compared to saline (P < 0.001). During hemorrhage, glucose-treated rats developed substantial hyperglycemia while glucose levels fell in saline treated (P < 0.001). Concomitant developments in hematocrits indicated improved plasma refill in glucose treated animals (P < 0.01). While saline treated rats developed irreversible shock and died within 3 hr of bleeding, glucose treated rats had a MAP of 52 +/- 2 (mean +/- SEM) mm Hg by the end of hemorrhage (P < 0.01). All glucose-treated rats recovered and survived the seven-day observation period. It is concluded that glucose infusion leading to hepatic glycogen repletion alters outcome after experimental hemorrhage in food deprived animals. These experimental results may be of clinical relevance, since elective surgery is generally performed after overnight fasting, which substantially reduces the hepatic glycogen reserve.
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PMID:Pretreatment with glucose infusion prevents fatal outcome after hemorrhage in food deprived rats. 848 72

Although an increased prevalence of hypertension is associated with insulin-dependent diabetes, little is known about the effect of streptozotocin (STZ) diabetes on arterial pressure (AP) regulation in rats. Changes in AP induced by STZ, as well as associated factors in blood pressure regulation such as baroreflex sensitivity, plasma renin activity (PRA), plasma glucose and insulin levels and endothelium participation, were studied in male Wistar rats weighing 287 +/- 10 g. The same seven conscious rats were used for all measurements before and after STZ diabetes. AP pulses were stored on a videotape recorder and processed by a data acquisition system. Baroreflex sensitivity was evaluated by measuring heart rate (HR) changes induced by AP variations produced by phenylephrine and sodium nitroprusside injection. The effect of inhibition of nitric oxide synthesis with NG-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg i.v. bolus plus infusion at 20 mg kg-1 h-1) on AP was evaluated in another set of rats (6 normal and 5 submitted to STZ treatment). STZ induced hyperglycemia (306 +/- 19 mg/dl), a reduction in mean arterial pressure (MAP, from 116 +/- 5 to 101 +/- 4 mmHg) and no changes in HR (320 +/- 10 vs 298 +/- 14 bpm). The tachycardic response to arterial pressure decreases was impaired (-2.29 +/- 0.5 vs -4.5 +/- 0.7 bpm/mmHg, in control) while the bradycardic response to arterial pressure increases was unchanged. Pressure responsiveness to phenylephrine was impaired after STZ (3.78 +/- 0.4 vs 6.73 +/- 0.8 mmHg microU-1 ml-1, in control).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Streptozotocin diabetes modifies arterial pressure and baroreflex sensitivity in rats. 852 May 49

The effect of perfusion with elevated glucose concentrations on hypoxic myocardium was investigated in isolated Langendorff guinea pig hearts. For that purpose, mechanical (heart rate, systolic peak pressure and coronary flow) and electrophysiological (monophasic action potential duration=MAP, ectopic beats) data were evaluated. At the end of the experiments the hearts were examined histologically after trypan blue vital staining for quantification of irreversible myocardial damage. In the absence of insulin moderate glucose elevation (from 5 to 15 mM) exerted beneficial effects on hypoxic hearts: the depressed contraction was improved, the action potential shortening partly reversed and the percentage of irreversibly damaged myocytes diminished. Glucose did not have any effect on heart rate and arrhythmias under hypoxia or reperfusion. A contribution of cardiac ATP-dependent K+ channels to the effects of glucose could be excluded by further experiments. Thus, blocking these channels with high glibenclamide concentrations did not affect the action of glucose on MAP and contraction. To some degree the glucose effect on MAP, but not on systolic pressure, was also observable under normoxic conditions.
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PMID:Effects of high glucose on the hypoxic isolated guinea pig heart: interactions with ATP-dependent K+ channels? 1021 42

The dependence of blood pressure on a balance between superoxide and nitric oxide may be amplified in diabetes. We have shown that the first occurrence of sustained hyperglycemia in type I diabetes causes hypertension when induced in rats that have had nitric oxide synthesis blocked chronically (L-NAME, 10 microg/kg per minute IV). This study used tempol (18 micromol/kg per hour IV) to test the hypothesis that superoxide mediates that hypertensive response. Induction of diabetes in untreated rats had no significant effect on mean arterial pressure (MAP, measured 18 h/d), and glomerular filtration rate (GFR) increased significantly during the 2 weeks of diabetes. Chronic infusion of L-NAME in a separate group of rats increased baseline MAP from approximately 90 mm Hg to a stable level of approximately 120 mm Hg after 6 days of infusion, and induction of diabetes (streptozotocin, 40 mg/kg IV) in those rats caused a rapid, progressive increase in MAP that averaged 156+/-5 mm Hg by day 14 of diabetes that was associated with a decrease in GFR and 4-fold increase in isoprostane excretion. Tempol infusion was begun on day 2 of diabetes in a subgroup of those rats, and the progressive hypertensive response was prevented, with MAP averaging 134+/-10 mm Hg by day 14. In addition, the normal renal hyperfiltration response was restored by tempol and the increase in isoprostane did not occur. Thus, the hypertension and decrease in GFR caused by onset of diabetes in rats without a functioning nitric oxide system was prevented by chronic administration of the superoxide dismutase mimetic tempol.
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PMID:Nitric oxide may prevent hypertension early in diabetes by counteracting renal actions of superoxide. 1465 52

Neurologic complications after severe brain injuries are the result of primary injuries in the moment of impact and secondary injuries which evolve over the minutes and days later. According to statistics, secondary injuries were documented in about 90 percent of patients who died after traumatic brain injury. Low oxygen delivery in hypotension, hypoxia, oedema, intracranial hypertension or changes in cerebral blood flow all account for development of secondary injuries. Primary injuries are more or less complete, but secondary injuries could be prevented with adequate therapy. Understanding mechanisms of secondary injuries could help identify potentially beneficial therapies. Important elements of therapy are: head position, normoglycemia, osmotherapy, normal body temperature, optimal blood pressure, adequate oxygenation, barbiturate therapy. Neutral head and neck position is recommended to prevent intracranial hypertension. Hyperglycemia with less ATP leads to ishaemic acidosis, hypoglycemia enhances decomposition of phospholipids and release of fat acids, what makes the cellular damage worse. Normocapnia is recommended and adequate oxygenation (PaO2 higher than 90%). To prevent dehydration and electrolyte imbalance, serum electrolytes should be examined every 4-6 h as well as osmolarity. Moderate therapeutic hypothermia could be of benefit, and maintaining of optimal blood pressure (MAP above 90 mmHg), especially in the first period after injury. As these have a lot of adverse effects, barbiturates are recommended only when conventional therapies show no effect. Patients should be hydrated well before induction of barbiturates. In organized trauma centers and with adequate intensive care the mortality from traumatic brain injury decreased from 50% in 1970, to about 30% now days.
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PMID:[Prevention of secondary brain injuries]. 1501 66

Because diabetic women appear not to be protected by estrogen in terms of propensity to cardiovascular disease, we tested the possibility that chronic hyperglycemia modulates the effects of E(2) on vascular cell growth in vitro. Human endothelial cells (E304) and vascular smooth muscle cells (VSMC) were grown in normal glucose (5.5 mmol/l), high glucose (22 mmol/l) or high manitol (22 nmol/l; an osmotic control) for 7 days. In endothelial cells glucose per se stimulated DNA synthesis. However E(2)- (but not RAL-) stimulated [3H] thymidine incorporation was attenuated in the presence of high glucose. In parallel, E(2)-dependent MAP-kinase-kinase activity was blocked in the presence of high glucose. High glucose increased basal creatine kinase (CK) specific activity, but E(2)-stimulated CK was not significantly impaired in the presence of high glucose. In VSMC, high glucose prevented the inhibitory effect of high E(2) (but not of high RAL) concentrations on DNA synthesis. High glucose also prevented E(2)-induced MAP-kinase-kinase activity. In contrast, while high glucose augmented basal CK, the relative E(2)-induced changes were roughly equal in normal and high high glucose media. Hence, high glucose blocks several effects of E(2) on vascular cell growth, which are mediated, in part, via the MAP-kinase system and are likely contributors to E(2)'s anti-atherosclerotic properties. Since RAL's estrogen-mimetic effects on human vascular cell growth were independent of MAP-kinase activation and were not affected by hyperglycemia, the potential use of RAL to circumvent the loss of estrogen function induced by hyperglycemia and diabetes in the human vasculature should be further explored.
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PMID:High glucose blocks the effects of estradiol on human vascular cell growth: differential interaction with estradiol and raloxifene. 1502 88

ACE inhibition protects kidney function, but ACE insertion/deletion (I/D) polymorphism affects renal prognosis in type 1 diabetic patients. ACE genotype may influence the renal benefits of ACE inhibition. We studied the impact of ACE I/D polymorphism on the renal hemodynamic changes induced by ACE inhibition in type 1 diabetes. We studied renal hemodynamics (glomerular filtration rate [GFR], effective renal plasma flow [ERPF], filtration fraction [GFR/ERPF], mean arterial pressure [MAP], and total renal resistances [MAP/ERPF]) repeatedly during normoglycemia and then hyperglycemia in 12 normotensive, normoalbuminuric type 1 diabetes and the II genotype (associated with nephroprotection) versus 22 age- and sex-matched subjects with the ACE D allele after three randomly allocated 2- to 6-week periods on placebo, 1.25 mg/day ramipril, and 5 mg/day ramipril in a double-blind, cross-over study. During normoglycemia, the hemodynamic changes induced by ramipril were similar in both genotypes. During hyperglycemia, the changes induced by ramipril were accentuated in the II genotype group and attenuated dose dependently in the D allele group (treatment-genotype interaction P values for ERPF, 0.018; MAP, 0.018; and total renal resistances, 0.055). These results provide a basis to different renal responses to ACE inhibition according to ACE genotype in type 1 diabetes.
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PMID:Modulation of the renal response to ACE inhibition by ACE insertion/deletion polymorphism during hyperglycemia in normotensive, normoalbuminuric type 1 diabetic patients. 1618 99

Neurologic complications after severe brain injuries are the result of primary injuries in the moment of impact and secondary injuries which evolve over the minutes and days later. According to statistics, secondary injuries were documented in about 90 percent of patients who died after traumatic brain injury. Low oxygen delivery in hypotension, hypoxia, oedema, intracranial hypertension or changes in cerebral blood flow all account for development of secondary injuries. Primary injuries are more or less complete, but secondary injuries could be prevented with adequate therapy. Understanding mechanisms of secondary injuries could help identify potentially beneficial therapies. Important elements of therapy are: head position, normoglycemia, osmotherapy, normal body temperature, optimal blood pressure, adequate oxygenation. barbiturate therapy. Neutral head and neck position is recommended to prevent intracranial hypertension. Hyperglycemia with less ATP leads to ishaemic acidosis, hypoglycemia enhances decomposition of phospholipids and release of fat acids, what makes the celulare damage worse. Normocapnia is recommended and adequate oxygenation (PaO2 higher than 90%). To prevent dehydration and electrolyte imbalance, serum electrolytes should be examined every 4-6 h as well as osmolarity. Moderate therapeutic hypothermia could be of benefit, and maintaining of optimal blood pressure (MAP above 90 mmHg), especiallz in the first period after injury. As thez have a lot of adverse effects, barbiturates are recommended only when conventional therapies show no effect. Patients should be hydrated well before induction of barbiturates. In organized trauma centers and with adequate intensive care the mortality from traumatic brain injury decreased from 50% in 1970, to about 30% nowdays.
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PMID:[Prevention of secondary brain injury]. 1652 33


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